Improvement in bleaching palm-leaf, straw



UNITED STATES PATENT ()FFICE FRANKLIN PERBIN, OF CAMBRIDGE, ASSIGNOR 'lO HIMSELF AND D. 0.

- PERRIN, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN BLEACHING PALM-LEAF, STRAW, 80C.

Specification forming part of Letters Patent No. 56,860, dated July 31, 1866.

To all whom it may concern:

Be it known that I, FRANKLIN PERRIN, of Cambridge, county of Middlesex, and State of Massachusetts, have invented an Improvement in Bleaching Palm-Leaf, Cane, Straw, and fibers of like kind, which facilitates the bleaching of such materials and protects the health of the workmen from injury; and I do hereby declare that the followingis a description of the same sufficient to enable those skilled in the art to practice my invention.

My improvement consists in the use of pure sulphurous acid in presence of humidity, instead of the usual mixture of sulphurous acid and atmospheric gases resulting from the combustion of sulphur in closed or partiallyclosed vessels or chambers.

It is well known that the mixture of gases (of which sulphurous acid forms a part) made by burning sulphur in a burner attached to or contained in a chamber filled with air has been employed as a bleaching agent, and after the bleaching of palm-leaf, straw, &c., has been effected the chamber is opened, and the workmen enter and remove the leaf or straw and refill the chamber for a new operation. In this way the workmen suffer from inhaling the remaining gas, andthe materials when bleached being damp, they are exposed to dampness and cooler currents of air.

Now, I have discovered that pure gaseous snlphurous acid, which had been supposed to act corrosively on palm-leaf and like fibers, may be used with safety even if all other gases are removed, and the effect of bleaching is very much hastened without risk in the course which I have adopted. By a slight change in the chambers or vessels used to contain the gas I remove any necessity for entering them, and thus avoid risk of health and annoyance of the workmen.

I will now proceed to describe one method of practicing my improvement, which method may be varied as circumstances may require.

Where only one room, chamber, or vessel has been heretofore used, I add two or more such chambers, or divide by partitions of plank large chambers, so as to insure greater depth than width and length, so that a rack or frame containing the longest material used can descend from above into it and yetleave about ten inches of free space over the rack or frame loaded with palm-leaf, cane, or straw, or like material. A ledge or trough of lead or wood is formed in the chamber at the top, so that when the roof or cover is placed upon the chamber its edge will dip into the trough filled with water and form a water-j oint. There may be three or more chambers, and, as now considered, each is closed and contains its rack loaded with the damp material to be bleached. At the upper part of each chamber a small pipe with a damper connects with the next chamber, and the last pipe opens to the air. Each chamber has a pipe near the bottom, which connects with the retort used for making the gas by means of a movable tube,- longer or shorter, as may be necessary.

At a convenient point is a glass retort, with its sand-pot, over afurnace, for producing the gas from oil of vitriol and sulphur. Fifty pounds of oil of vitriol and sixteen pounds of refined sulphur placed in the retort, and fire sustained until the oil of vitriol boils, the pure sulphurous-acid gas will flow from the neck of the retort into the bottom of the chamber with which it is connected. Entering at the bottom, it lifts out the lighter air through the pipe with open valve into the next chamber, and, after filling the first chamber, any excess flows into the next, and so on, the receivingchamber being always open to one or more chambers and the outer air afterward.

At a little trial-hole in each chamber the bleaching in the chamber of pure gas can be watched, and when completed the movable pipe is connected with the pipe of the second chamber, which had been closed, and the gas passes into the second chamber. At the instant of removing the movable pipe from the first chamber the lower pipe and valve are closed, thus shutting in the heavy gas.

By slowly lifting the roof or cover off, then raising by crane the rack filled with bleached material, the chamber is prepared to receive a rack of fresh damp material to be bleached, while that which has been bleached can now be washed and dried. This course can be followed continuously as the gas flows, or it may be intermitted with a slight loss of gas, which, from its weight, remains like a liquid in the deep chambers.

Q I solace The overflow of gas falls into the next chamber to that which is working, and there spends itself on the fresh material, while the air which had filled the vessel escapes finally to the open air. In this way the completion'of the process takes place in nearly pure gas, and the fresh material I find may be acted upon directly by pure gas in one chamber if an outlet for the air has been provided.

The chambers may be lined with lead or Wooden walls imbued with asphaltic varnish, and the sulphurous acid may be prepared in any way, affording a nearly pure gas, such as V sulphuric acid and charcoal produce, or such as a solution of the gas in water gives off by heat.

It will be seen that my invention relates to the use of pure or nearly pure sulphurous-acid gas for bleaching such fibrous bodies as were hitherto supposed to be injured and corroded by strong and pure gas, which bodies, before my invention, have been exposed to gas largely diluted with air, or nitrogen gas only, for the purpose of bleaching them.

I do not claim the application of this pure gas to silken or woolen fibers whose nature is different, but confine it to the fibrous parts of plants, and thus greatly shorten the time of immersion in gas or fluid acid without the slightest injury to fibers.

What I claim as my invention is The improvement in bleaching palm-leaf, cane, straw, and similar fibrous bodies, substantially as described.

FRANKLIN PERRIN.

Witnesses:

F. GOULD, J. O. HARRIS. 

